Finding covers for the PRS-350 seems harder even than for the other Sonys, since the 950 and 650 can use legacy covers from other devices. Manufacturing on the PRS line's accessories was cut down by the disaster in Japan and by the recession, so they were fairly scarce to begin with.

You can try any of the leather covers on Amazon, but most of them seem too bulky to me. If you want something nicer and slimmer, try an oiled stone leather cover from Hidden Mountain Curriers (you can ask for different shades of leather; he also does custom designs): http://www.etsy.com/listing/74505832...y-prs-350-case